import router from '@/router'
const state = {
  visitedViews: [],
  cachedViews: [],
  cacheInstance: {},
  iframeViews: [],
  backViews: {},
  backViews_title: {},
}

// 上一个路由
let prevRoute = null
// 当前路由
let currentRoute = null

const mutations = {
  ADD_IFRAME_VIEW: (state, view) => {
    if (state.iframeViews.some(v => v.fullPath === view.fullPath)) return
    state.iframeViews.push(
      Object.assign({}, view, {
        title: view.meta.title || 'no-name'
      })
    )
  },
  ADD_VISITED_VIEW: (state, view) => {
    prevRoute = currentRoute
    currentRoute = view.fullPath || null
    if (!view.fullPath || state.visitedViews.some(v => v.fullPath === view.fullPath)) return
    let nowIndex = state.visitedViews.findIndex(v => v.fullPath === prevRoute)
    nowIndex = ~nowIndex ? nowIndex + 1 : state.visitedViews.length
    const newView = Object.assign({}, view, { title: view.meta.title || 'no-name' })
    state.visitedViews.splice(nowIndex, 0, newView)
  },
  ADD_CACHED_VIEW: (state, view) => {
    if (state.cachedViews.includes(view.fullPath)) return
    if (view.meta && !view.meta.noCache) {
      state.cachedViews.push(view.fullPath)
    }
  },
  DEL_VISITED_VIEW: (state, data) => {
    const [view, deleteBack] = Array.isArray(data) ? data : [data, true]
    for (const [i, v] of state.visitedViews.entries()) {
      if (v.fullPath === view.fullPath) {
        state.visitedViews.splice(i, 1)
        deleteBack && mutations.DEL_CHAIN_BACK_VIEWS(state, view.fullPath)
        break
      }
    }
    state.iframeViews = state.iframeViews.filter(item => item.fullPath !== view.fullPath)
  },
  DEL_IFRAME_VIEW: (state, view) => {
    state.iframeViews = state.iframeViews.filter(item => item.fullPath !== view.fullPath)
  },
  DEL_CACHED_VIEW: (state, view) => {
    const index = state.cachedViews.indexOf(view.fullPath)
    index > -1 && state.cachedViews.splice(index, 1)
  },

  DEL_OTHERS_VISITED_VIEWS: (state, view) => {
    state.visitedViews = state.visitedViews.filter(v => {
      if (v.fullPath === view.fullPath) return true
      mutations.DEL_CHAIN_BACK_VIEWS(state, v.fullPath)
    })
    state.iframeViews = state.iframeViews.filter(item => item.fullPath === view.fullPath)
  },
  DEL_OTHERS_CACHED_VIEWS: (state, view) => {
    const index = state.cachedViews.indexOf(view.fullPath)
    if (index > -1) {
      state.cachedViews = state.cachedViews.slice(index, index + 1)
    } else {
      state.cachedViews = []
    }
  },
  DEL_ALL_VISITED_VIEWS: state => {
    // keep affix tags
    const affixTags = state.visitedViews.filter(tag => tag.meta.affix)
    state.visitedViews = affixTags
    state.iframeViews = []
    mutations.DEL_ALL_BACK_VIEWS(state)
  },
  DEL_ALL_CACHED_VIEWS: state => {
    state.cachedViews = []
  },
  UPDATE_VISITED_VIEW: (state, view) => {
    for (let v of state.visitedViews) {
      if (v.fullPath === view.fullPath) {
        v = Object.assign(v, view)
        break
      }
    }
  },
  DEL_RIGHT_VIEWS: (state, view) => {
    const index = state.visitedViews.findIndex(v => v.fullPath === view.fullPath)
    if (index === -1) {
      return
    }
    state.visitedViews = state.visitedViews.filter((item, idx) => {
      if (idx <= index) {
        return true
      }
      const i = state.cachedViews.indexOf(item.fullPath)
      if (i > -1) {
        state.cachedViews.splice(i, 1)
        mutations.DEL_CHAIN_BACK_VIEWS(state, item.fullPath)
      }
      if(item.meta.link) {
        const fi = state.iframeViews.findIndex(v => v.fullPath === item.fullPath)
        state.iframeViews.splice(fi, 1)
      }
      return false
    })
  },
  DEL_LEFT_VIEWS: (state, view) => {
    const index = state.visitedViews.findIndex(v => v.fullPath === view.fullPath)
    if (index === -1) {
      return
    }
    state.visitedViews = state.visitedViews.filter((item, idx) => {
      if (idx >= index) {
        return true
      }
      const i = state.cachedViews.indexOf(item.fullPath)
      if (i > -1) {
        state.cachedViews.splice(i, 1)
        mutations.DEL_CHAIN_BACK_VIEWS(state, item.fullPath)
      }
      if(item.meta.link) {
        const fi = state.iframeViews.findIndex(v => v.fullPath === item.fullPath)
        state.iframeViews.splice(fi, 1)
      }
      return false
    })
  },
  ADD_BACK_VIEWS: (state, view) => {
    state.backViews[view] = router.currentRoute.fullPath
  },
  DEL_BACK_VIEWS: (state, view) => {
    delete state.backViews[view]
  },
  DEL_CHAIN_BACK_VIEWS: (state, back) => {
    while (state.backViews[back]) {
      const newBack = state.backViews[back]
      delete state.backViews[back]
      delete state.cacheInstance[newBack]
      back = newBack
    }
  },
  DEL_ALL_BACK_VIEWS: (state) => {
    Object.entries(state.backViews).forEach(([item, value]) => {
      delete state.cacheInstance[value]
      delete state.backViews[item]
    })
  }
}

const actions = {
  addView({ dispatch }, view) {
    dispatch('addVisitedView', view)
    dispatch('addCachedView', view)
  },
  addIframeView({ commit }, view) {
    commit('ADD_IFRAME_VIEW', view)
  },
  addVisitedView({ commit }, view) {
    commit('ADD_VISITED_VIEW', view)
  },
  addCachedView({ commit }, view) {
    commit('ADD_CACHED_VIEW', view)
  },
  delView({ dispatch, state }, view) {
    return new Promise(resolve => {
      dispatch('delVisitedView', view)
      dispatch('delCachedView', view)
      resolve({
        visitedViews: [...state.visitedViews],
        cachedViews: [...state.cachedViews]
      })
    })
  },
  delVisitedView_only({ commit }, view) {
    commit('DEL_VISITED_VIEW', [view])
  },
  delVisitedView({ commit, state }, view) {
    return new Promise(resolve => {
      commit('DEL_VISITED_VIEW', view)
      resolve([...state.visitedViews])
    })
  },
  delIframeView({ commit, state }, view) {
    return new Promise(resolve => {
      commit('DEL_IFRAME_VIEW', view)
      resolve([...state.iframeViews])
    })
  },
  delCachedView({ commit, state }, view) {
    return new Promise(resolve => {
      commit('DEL_CACHED_VIEW', view)
      resolve([...state.cachedViews])
    })
  },
  delOthersViews({ dispatch, state }, view) {
    return new Promise(resolve => {
      dispatch('delOthersVisitedViews', view)
      dispatch('delOthersCachedViews', view)
      resolve({
        visitedViews: [...state.visitedViews],
        cachedViews: [...state.cachedViews]
      })
    })
  },
  delOthersVisitedViews({ commit, state }, view) {
    return new Promise(resolve => {
      commit('DEL_OTHERS_VISITED_VIEWS', view)
      resolve([...state.visitedViews])
    })
  },
  delOthersCachedViews({ commit, state }, view) {
    return new Promise(resolve => {
      commit('DEL_OTHERS_CACHED_VIEWS', view)
      resolve([...state.cachedViews])
    })
  },
  delAllViews({ dispatch, state }, view) {
    return new Promise(resolve => {
      dispatch('delAllVisitedViews', view)
      dispatch('delAllCachedViews', view)
      resolve({
        visitedViews: [...state.visitedViews],
        cachedViews: [...state.cachedViews]
      })
    })
  },
  delAllVisitedViews({ commit, state }) {
    return new Promise(resolve => {
      commit('DEL_ALL_VISITED_VIEWS')
      resolve([...state.visitedViews])
    })
  },
  delAllCachedViews({ commit, state }) {
    return new Promise(resolve => {
      commit('DEL_ALL_CACHED_VIEWS')
      resolve([...state.cachedViews])
    })
  },
  updateVisitedView({ commit }, view) {
    commit('UPDATE_VISITED_VIEW', view)
  },
  delRightTags({ commit }, view) {
    return new Promise(resolve => {
      commit('DEL_RIGHT_VIEWS', view)
      resolve()
    })
  },
  delLeftTags({ commit }, view) {
    return new Promise(resolve => {
      commit('DEL_LEFT_VIEWS', view)
      resolve()
    })
  },
  addBackViews({ commit }, view) {
    commit('ADD_BACK_VIEWS', view)
  },
  delBackViews({ commit }, view) {
    commit('DEL_BACK_VIEWS', view)
  },
  delChainBackViews({ commit }, view) {
    commit('DEL_CHAIN_BACK_VIEWS', view)
  }
}

export default {
  namespaced: true,
  state,
  mutations,
  actions
}
